1. Field of the Invention
This invention relates to a device for detecting a voltage of a battery used in electronic apparatus and appliances, the circuit of which is driven in part or whole by a battery, and for displaying a voltage condition as detected.
1. Description of Prior Art
There have so far been proposed several systems for detecting a voltage of a power source such as, for example, a battery to be used for electronic apparatus and appliances such as electronic desk calculators, etc. One example of such battery voltage detecting system reads the voltage of a battery to be used with an AD converter, etc., and feeds the read-out data into a control circuit, a CPU, and so forth of the electronic apparatus, the battery voltage being indicated by the control circuit, or directly by a voltmeter, or by a liquid crystal display device, in which the data display changes its density depending on a level of voltage due to the voltage dependent property of liquid crystal. Such system of indicating the battery voltage through the control circuit, however, imposes more load on the control circuit, and further necessitates high-priced component parts such as the AD converter, etc., on account of which the system is not entirely satisfactory for the battery voltage detection. On the other hand, the system of using the voltmeter, etc., has shortcomings such that an exclusive circuit other than the control circuit is used, or the voltage data are constantly on display even when they are not needed, which is troublesome to the eyes of an operator.